1. Field of the Invention
This invention relates to a device for separating stacked sheets, and more particularly to a device for separating photosensitive sheet material accumulated in a stack.
2. Description of the Prior Art
In the manufacture of photosensitive sheet materials such as X-ray film, comparatively large sized photographic film and so forth, it is often required to separate stacked sheets. Particularly, in the process of cutting the sheet material and the process of cutting the corners thereof to round them, the stacked sheets are likely to stick to each other and prevent smooth separation thereof. Sheets of photosensitive sheet material bearing a photographic emulsion layer are particularly apt to stick together since the surface of the emulsion layer is likely to be tacky.
In order to separate the stacked sheets, it has been known in the art to use an air blow as disclosed in Japanese Pat. No. 27249/1969. In this patent, a number of air blowing ports are provided on three sides of a stack of sheets on a sheet holder which is vibrated in the horizontal direction, and an air blow is applied to the edge of the stacked sheets to separate the sheets. This method of separating the sheets is disadvantageous in that the force acting to separate the sheets is weak since the cross sectional area of the air blowing ports is large, and a number of ports must be provided accordingly. Further, since the sheets are horizontally oriented and stacked vertically, the sheets in the uppermost part of the sheet stack are apt to be blown away by the air blow, and the sheets in the lower part of the sheet stack are far more difficult to separate than those in the upper part thereof. In addition, manual operation is required to align the sheets after separation.
It has also been known in the art to separate stacked sheets by a mechanical device as disclosed in Japanese Pat. No. 9061/1969. In this patent, it is disclosed to provide a movable member underneath a stack of sheets which are vertically oriented and accumulated in the horizontal direction so that some of the stacked sheets may be moved upward by the movable member as the member moves horizontally along the lower edge of the sheets. The movable member is screw-engaged with a screw rod extending perpendicular to the face of the sheets and moved along the lower side of the stack of the sheets by the revolution of the screw rod. This method of separating the stacked sheets is disadvantageous in that the lower edges of the sheets are apt to be scratched by the movable member since the movable member is moved in contact therewith. Further, this mechanical sheet separating device has a defect in that the speed of operation cannot be increased beyond a comparatively low speed.